Manufacture of wrought iron



Sept. 13, 1938. E. B; 5mm ET AL 9,711

7 MANUFACTURE OF WROUGHT IRON Filed March 50, 1937 I SHOTTING STATION CONVERTERS INVENTJORS Bab ward .BStory fvardflfiest CUPQ-DLAS Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE MANUFACTURE OF WROUGHT IRON sylvania Application March 30, 1937, Serial No. 133,809

9 Claims.

This invention relates to the manufacture of wrought iron, and more particularly to the manufacture of wrought iron by the now well known Aston process in which molten ferrous material is admixed with molten slag to form a wrought iron sponge ball.

In carrying out the Aston process the speed at which the various operations are performed and the ability to maintain such speed uniform are of great importance. The speed of operation and the uniformity of such speed are important both from the standpoint of economy and from the standpoint of temperature control, which is directly related to the quality of the product. For years A. M. Byers Company has been seeking to increase the economy of the process by increasing the speed of operation, but prior to the present invention the speed of operation has been undesirably slow. Moreover, the speed of operation has to a considerable extent been nonuniform due to conditions obtaining in the process as heretofore practiced which have inevitably resulted in substantial time lags. Such time lags have detrimentally affected temperature control and, consequently, the quality of the wrought iron produced.

We have discovered that by utilizing an entirely different procedure than heretofore we can greatly increase the speed of operation of the Aston process and also insure much greater uniformity of speed, thereby at thesame time increasing the economy of the process and insuring the necessary close temperature control and, consequently,.

the production of wrought iron of uniformly high quality.

The basic features of the Aston process are adhered to,that is to say,. we still admix molten ferrous material and molten slag to form a wrought iron sponge ball. We also preferably follow the teachings of the earlier Aston patents by introducing molten ferrous material into a bath of molten slag to form the ball. The molten ferrous material and molten slag are basically the same as those which have heretofore been used, but the manner of manipulating the slag receptacles and the handling and returning of the excess slag are entirely different. We have discovered that by shifting the slag receptacles to and from the processing station in'such manner that at least one thereof is disposed at the processing station at all times so as to be available to receive ferrous material supplied from the source of ferrous material we can eliminate time lags which heretofore have seriously interfered with the speedy and uniform operation of the process.

We find that best results are obtained by employing fewer active slag receptacles than heretofore and reducing the number of processing or 5 shutting machines in operation. We prefer to employ only two processing machines and only two active slag receptacles. By active slag receptacles we mean receptacles which at any given time contain wrought iron sponge balls or 10 have such balls in the process of formation therein. We preferably manipulate. the two active slag receptacles in such a way that substantially at all times ferrous material is being introduced into at least one thereof to form a ball. When optimum operation is obtained the ball-formin step is completed in one slag receptacle substantially simultaneously with the arrival of the other slag receptacle at the processing station, and ball formation in the second slag receptacle commences immediately, the first slag receptacle being forthwith removedto the slag transfer station. -By the time the ball-forming operation is completedin the second slag receptacle another slag receptacle (which may be the first slag receptacle but which, as will presently be described, ispreferably a different slag receptacle substituted in place of the first Slag receptacle) arrives at the processing station and the cycle is thus repeated substantially continuously without any appreciable time lag during which processing is not taking place.

The mode of operation above mentioned is found to considerably-increase the quantity of wrought iron produced during a given time. It avoids time lags in the process, particularly in the supplying of ferrous material. A much closer temperature control is obtainable and a higher quality product produced.

, Due to the increased speed of operation we find it desirable to take certain measures heretofore not employed to control the slag temperature,-that is, to prevent the slag temperature from rising to the point at which the proper temperature differential between the ferrous material and the slag is no longer obtained. It has long been appreciated that a proper temperature differential is essential to production of wrought iron of high quality. With the speeded-up process the slag temperature tends to increase beyond the proper temperature for admixture with the molten ferrous material, and we take certain novel steps to counteract this tendency.

We prefer to maintain a supply of slag receptacles in addition to the number of slag receptacles apparently required for carrying out the process, which slag receptacles are relatively cold as compared with those in use, and to substitute slag receptacles from such supply for the slag receptacles which have become highly heated in use. The frequency with which the slag receptacles are thus changed and the number of slag receptacles in the supply above mentioned furnishes a definite control for the slag temperature. We find it highly desirable when removing a slag receptacle from active use to allow the same to remain inactive and cool off during a plurality of cycles of the process.

We may also employ either separately or in conjunction with the methodjust mentioned another method of controlling the temperature of the slag, this being by incorporating with the molten slag quantities of cold solidified slag intermediate ball-forming operations as described and claimed in our copending application Serial No. 133,808, filed of even date'herewith. On occasions both the supplying of cold solidified slag intermediate ball-forming operations and the replacement of heated slag receptacles by relatively cold slag receptacles as above explained is found desirable to obtain the proper slag temperature control.

Other details, objects and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof and certain present preferred methods of practicing the same proceeds.

In the accompanying drawing we have shown diagrammatically a present preferred plant arrangement for carrying out the invention.

The general layout of the plant, as indicated diagrammatically in the drawing, is similar to that,described in detail in the copending application of Herman A. Brassert, Serial No. $26,984:, filed July 30, 1932, which has matured into Patent 2,095,965. .We shall describe herein only the more important apparatus, the auxiliary apparatus and the details of operation of the plant being described in said Brassert application.

The ferrous material for making the wrought iron is supplied by three cupolas designated generally by reference numeral 2. The molten ferrous material from the cupolas is transported on a track 3 to one or both of a pair of Bessemer converters 1 into which it is charged. The converters may be used alternately or one of them only may be used during a given operating period,

tion at which is an elevated platform 5 having mounted thereon five processing or shotting ma chines designated generally by reference numerals 6a, 6b, 6c, 6d and 6e, respectively. The processing station and the processing machines are preferably substantially as described in said Brassert application and in Wille Patent No. 1,933,577 and hence will not herein be described in detail.v Each processing machine preferably comprises a lip-pour ladle which, as it pours, oscillates angularly and also longitudinally of the machine. There is an opening in the platform 5 through which each of the processing machine ladles pours its contents during the processing operation.

At a level below. the level of the platform 5 is an oval track 1 a portion of which passes beneath the platform and beneath the openings in the platform through which the procwsing ladles pour their contents during the processing operatlon; Operating on the track I is a single motive unit indicated diagrammatically as an engine 8 which may be a steam or electric engine or other suitable motive unit operable in both directions as indicated by the arrow A. There are also provided four trucks or cars for carrying slag receptacles, such cars being designated generally by reference numerals 9a, 9b, 9c and 9d, respectively. Such cars are disposed in two groups of two each, the engine 3 being disposed between such two groups. One group comprises the cars to and 9b and the other group the cars and 9d, as shown.

Reference numeral Ill indicates an overhead crane operable on tracks l i and adapted to carry and manipulate a suitable transfer container such as a ladle to transfer the refined ferrous material from the converters 4 to the processing machine ladles. Reference numeral l2 designates a press into which the wrought iron sponge balls are dumped as will presently be described. Reference numeral l3 designates a pair of slag furnaces for supplying molten slag suitable for admixture with the molten ferrous material supplied by the converters d to form wrought iron sponge balls. Reference numerals M and i5 designate respectively a pair of overhead cranes operating on tracks it for purposes to be presently. described. Reference numeral l'l designates generally a supply of slag receptacles disposed at a convenient location within the oval track l and adapted for use in a manner to be described. I

As mentioned above, the general plant layout is substantially the same as that disclosed in said Brassert application and therefore minor details are being omitted from the present description. We shall now proceed to describe our preferred method of operation whereby the advantages above pointed out are obtained.

Assuming that the two converters 4 are tapped alternately, the refined ferrous material delivered by each is transferred in a transfer container such as a ladle, which may, for example, be moved on a buggy along the track 3 to a position generally opposite the platform 5, where it may be lifted by the overhead crane Hi. In our preferred method of operation we utilize only the two outside processing machines to and 66 of the group of five, the three interior processing machines 6b, 6c and 611 not being used. The entire group of five is shown simply because the plant is in general the same as is disclosed in said Brassert application and was designed for five machines; moreover, under certain circumstances we may utilize more than two machines as will be explained below, although this is not at present preferred. We find that the best results are obtained by using only the two outside processing machines.

At the beginningjof a run a portion (for example, half) of the contents of the transfer container is poured, let ussay, into the ladle of the left-hand processing machine 60. At such time the two cars 9a and 9b to the left of the engine 8, operatively speaking, and considering the plant as shown in the drawing, are disposed at the processing station with one of such cars, for example, the car 9a beneath the processing ma chine 6a and carrying a slagreceptacle containing a bath of molten slag at proper temperature for admixture with the molten ferrous material supplied from the converters for formation of a wrought iron sponge ball. As soon as the portion of the contents of the transfer container above mentioned has been transferred to the ladle of the processing machine 6a such processing machine commences operation, pouring such ferrous material into the slag bath in the slag receptacle above mentioned. The transfer container then immediately moves over and pours another portion (for example, the remainder) of its contents into the ladle of the right-hand processing machine lie. The transfer. container is then returned to receive the refined ferrous ma terial tapped from the converter other than that just previously tapped.

As soon as the processing machine 6a has completed itsoperation the engine pushes the two cars 9a and 9b toward the left to a position adjacent the press [2 as shown in the drawing. As soon as the train stops the overhead crane It sets down on the car 91), which is initially empty, an empty slag receptacle. The overhead crane then picks up from the car So the slag receptacle containing the ball, and which also contains excess slag in accordance with the normal operation of the Aston process, and decants the excess slag into the empty slag receptacle which it has just set down on the car 9b. Immediately upon completion of the decanting operation the train moves back to a position with the car 9b underneath the processing machine 6a. During the movement of the train from the processing station to the position adjacent the press, the decanting operation and the return movement of the train, the transfer container has brought an-' I returns to the processing station so that substantially as soon as the car 9b containing the slag receptacle with the decanted slag in it is spotted under the processing machine 6a such machine iii commences operation to repeat the cycle.

Meanwhile, the overhead crane I4 dumps the wrought iron sponge ball from the slag receptacle used for the first processing operation into the press 12, wherein the sponge ball is compressed into a bloom, after which the bloom is removed to the blooming mill. At the same time as this is happening, and also during the movements of the train previously described, the processing machine Be is in operation pouring the contents of its ladle into a slag receptacle containing a slag bath positioned on one of the two right-hand cars and 9d, for example the car So, which is spotted underneath the processing machine 6e. Such processing machine completes its operation about the time the car 9b with the slag receptacle containing the decanted slag is spotted under the processing machine (in. After such car is spotted the engine is uncoupled from the two left-hand cars, moved toward the right, viewing the drawing, a short distance to enable it to be coupled to the two right-hand cars, and it is then coupled to such cars and the train comprising the engine and the two right-hand cars is then moved toward the right to a position adjacent the slag furnaces. The overhead crane l4 sets down on the empty car 9d an empty slag receptacle, which may be the slag receptacle from which the previously mentioned ball was dumped into the press or one of the slag receptacles from the supply located within the oval track, as will presently be exp-lained, and then picks up from the car 90 the slag receptacle containing the ball just formed beneath the processing machine 6e and decants the excess slag into the slag receptacle which has just been set down on the car 9d. As soon as the decanting operation iscompleted the train immediately moves back to the processing station and the car 9d carrying the slag receptacle containing the decanted slag is spotted underneath the processing machine 6e. The ball is dumped into the press as before.

As will be seen from the above description, our preferred method of procedure can apparently be carried out using only three slag receptacles,- that is, if no question of temperature control were involved, three slag receptacles would be sufficient. The slag receptacles in which a ball is formed in one processing operation at one of the processng machines may be used to receive the decanted slag from the succeeding processing operation at the other processing machine and thus alternate in ball-forming operations between the two processing machines. cally, disregarding the question of temperature control, each of the three slag receptacles would be used in the same way and the process would go on indefinitely. Due, however, to the. increased speed of the operation, the fact that the slag is from time to time replenished with additional molten slag, as will presently be described, and the relatively large size of the balls which are produced, the slag receptacles heat up undesirably and the increased temperature of the slag receptacles Theoretiresults in the gradual building up of the temperature of the slag bath. The molten ferrous material which is poured into the slag is at a. temperature substantially higher than the slag and heats up the slag. Heretofore the time lags have generally been sufficient to allow the slag to cool off so that its temperature does not build up undesirably,-that is to say, the heat losses in the slag due to the slowness of the operation have compensated for the heat gains from the molten ferrous material. However, as pointed out above, the process was unsatisfactory from the standpoint of economy and the speed of operation was not uniform, resulting at times in the production of wrought iron of poor quality which could not be used.

The tendency of the slag receptacles to heat up is preferably counteracted by substituting from time to time a relatively cold slag receptacle from the supply H for one of the slag receptacles which has become heated. When it-is desired to make such a substitution the heated slag receptacle after the ball has been dumped therefrom is preferably set down on the fioor and .one of the relat vely cold slag receptacles from the supply I! is picked up and used in its place, the process otherwise continuing exactly as above described. If desired the excess slag from a slag receptacle containing a ball may be decanted directly into a relatively cold slag receptacle while still in place at the location of the supply l1, after which the ball may be dumped, the receptacle from which the ball was dumped set down at the location of the supply I! and the receptacle into which the excess slag was decanted picked the train as soon as the train stops at the slag transfer station.

It will be appreciated that a regular procedure can be worked out to control the slag temperature for any particular speed of operation employed. The frequency with which the heated slag receptacles are replaced by relatively-cold slag receptacles and the number of slag receptacles in the supply I! can be such that the total numberof slag receptacles can be continuously rotated in use. If, for example, a total of eleven slag receptacles is employed, three of these will be in use at any one time. The other eight will constitute the supply from which relatively cold slag receptacles are taken. Each time a heated slag receptacle is replaced by a relatively cold slag receptacle the heated slag receptacle may take its place in rotation and will go into active use again at the eighth change thereafter. Meanwhile it will be cooling off so that when it again'goesinto active use it will be relatively cold as the term is employed herein.

As mentioned above, the slag is from time to time replenished by additional molten slag from the slag furnaces 13. This slag is preferably delivered in a ladle carried by the crane l5. Ordinarily it is most convenient to effect replenishment by delivering the replenishing slag into an .empty slag receptacle,. which may be a slag receptacle from which a ball has justbeen dumped or a relatively cold slag receptacle from the supply l'l. This may be done during the time interval between the dumping of the ball formed in the preceding processing operation at one of the processing machines and the decanting into the slag receptacle of the excess slag from the next processing operation at the other processing machine. Slag replenishment may, however, be effected at any convenient point in the cycle. For example, the replenishing slag may be introduced into a slag receptacle after processing therein and before decanting, or it may be introduced simultaneously with decanting, or it may be introduced into a slag receptacle containing decanted slag after decanting.

Also, as mentioned above, the process of temperature control disclosed in our said copending application may be employed either alone or in conjunction with the method of temperature control above described. In our said copending application there is described and claimed a method of temperature control which comprises incorporating with the molten slag quantities of cold solidified slag intermediate ball-forming operations. If balls of comparatively large size are being produced and the process is being operated at high speed it may be desirable to combine both methods of temperature control.

The lower portion of the oval track 1, viewing,

the drawing, is not used at all in our preferred method of operation. It is shown in the drawing because it is a part of the track actually employed at the Ambridge plant of A. M. Byers Company. It may on occasion be used to cope with particular situations which may arise.

As explained above, the use of only two active slag receptacles at any one time is preferred because this has been found to give the highest efficiency. When only two active slag receptacles are employed at one time and the process is properly synchronized as above described, processing into one or the other of the two active slag receptacles will be substantially continuous. If for any reason it is found necessary to slightly reduce the speed of the operation this can be done only handle one slag receptacle at a time, so itis inevitable that the greater the number of active slag receptacles employed at any one time the greater will be the time lagduring decanting and dumping of the balls into the press.

While we have shown-and described'certain present preferred embodiments of the'invention and certain present preferred methods of practicing the same, it is to be'distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims.

We claim: 1. In the manufacture of wrought iron by th Aston process wherein molten ferrous material is introduced into receptacles containing molten slag at a processing station to form wrought iron sponge balls, the steps comprising alternately moving slag containing receptacles to the processing station along' difierentpaths and so that at. least one thereof is disposed at the processing station at all timeaintroducing ferrous material into said receptacles at the processing station, re-

moving said receptacles from the processing. station after introduction of the ferrous material thereinto and removing the balls therefrom.

2. In the manufacture of wrought iron by the Aston process wherein molten ferrous material is introduced into receptacles containing molten slag at a processing station to form wrought iron sponge balls, the steps comprising supplying molten ferrous material to said processing smtion in a container, transferring a portion'of'the molten ferrous material in said container into a pouring receptacle at the 'processing' station, simultaneously with said transference pouring ferrous material from another pouring receptacle at said processing station into a slag receptacle containing a bath of molten slag, and thereafter transferring another portion of the molten ferrousmaterial in said container into said sec-. ond mentioned pouring receptacle, and simultaneously with said second mentioned transference pouring the ferrous material previously transferred into the first mentioned pouring receptacle into another slag receptacle containing a bath of molten slag and also simultaneously with said second mentioned pouring step removing the ball from the first mentioned slag receptacle and I providing a bath of molten slag for the succeeding pouring operation from said second mentioned pouring receptacle.

3. In the manufacture of wrought iron by the Aston process, the steps comprising admixing molten ferrous material with quantities of molten slag more than suflicient to form with theferrous material wrought iron sponge balls and thereby forming wrought iron sponge balls with excess molten slag, separating the balls and excess slag, utilizing the excess slag in preparation of baths of molten slag and subsequent ball-forming operations and maintaining the slagbaths at such temperature as to insure proper ball formation by cooling the, same by substituting intermediate ball-forming operations relatively cold receptacles for the receptacles containing the slag baths and which have become undesirably heated due to the heat of the molten slag and ferrous material.

- 4. In the manufacture pf wrought iron by the Aston process wherein molten ferrous material is introduced at a processing station into receptacles containing quantities of molten slag more than sufficient to form with the ferrous material wrought iron sponge balls and thereby forming wrought iron sponge balls with excess molten slag, the steps comprising shifting said receptacles to and from the processing station in such manner that at least one thereof is disposed at the processing station at all times, introducing ferrous material into said receptacles at the processing station, separating the balls and excess slag, utilizing the excess slag in preparation of baths of molten slag for subsequent ballforming operations and maintaining the slag baths at such temperature as to insure proper ball formation by cooling the same by substituting intermediate ball-forming operations relatively cold receptacles for the receptacles containing the slag baths and which have become undesirably heated due to the heat of the molten slag and ferrous material.

5. In the manufacture of wrought iron by the Aston process, the steps comprising admixing in a receptacle molten ferrous material with a quantity of molten slag more than sufficient to form with the ferrous material a wrought iron sponge ball and thereby forming a wrought iron sponge ball with an excess of molten slag, separating the ball and the slag in the receptacle not incorporated in the ball, utilizing such slag as at least a part of a quantity of molten slag for admixture with ferrous material to form another wrought iron sponge ball, disposing such quantity of molten slag in a receptacle which is relatively cold in comparison with said first mentioned receptacle, admixing .molten ferrous material with such slag in said second mentioned receptacle to form said second mentioned wrought iron sponge ball and allowing said first mentioned receptacle to cool during a plurality of cycles of the process before returning it to use.

6. In the manufacture of wrought'iron by the Aston process, the steps comprising admixing in a receptacle molten ferrous material with a quan- ,wrought iron sponge ball, disposing such quantity of molten slag in a receptacle from said supply which has remained unused during a plurality of cycles of the process, and admixing molten ferrous material with such slag in said last men-' tioned receptacle to form said second mentioned wrought iron sponge ball.

7. In the manufacture of wrought iron by the Aston process wherein molten ferrous material is introduced at a processing station into receptacles containing quantities of molten slag more than 'suflicient to form with the ferrous material wrought iron sponge balls, the steps comprising shifting said receptacles to and from the processing station in such manner that at least one thereof is disposed at the processing station at all times, introducing ferrous material into said receptacles at the processing station, providing a supply of receptacles in addition to the number of receptacles apparently required for carrying out the process, separating the ball formed in one of said first mentioned receptacles and the slag in such receptacle not incorporated in the ball, utilizing such slag as at least a part of a quantity of molten slag for admixture with ferrous material in a subsequent ball-forming operation and, prior to such subsequent ball-forming operation, disposing such quantity of molten slag in a receptacle from said supply which has remained unused during a plurality of cycles of the process.

8. In the manufacture of wrought iron by the Aston process wherein molten ferrous material H is introduced into receptacles containing molten Aston process wherein molten ferrous material is introduced into receptacles containing molten slag at a processing station to form wrought iron sponge balls, the steps comprising supplying a quantity of molten ferrous material to a pouring receptacle at the processing station, simultaneously with said supplying step pouring the ferrous material from another pouring receptacle at said processing station into a slag receptacle containing a bath of molten slag, and thereafter supplying another quantity of molten ferrous material to said second mentioned pouring receptacle, and simultaneously with said second mentioned supplying step pouring the ferrous material previously supplied to the first mentioned pouring receptacle into another slag receptacle containing a bath of molten slag and also simultaneously with said second mentioned pouring step removing the ball from the first mentioned slag receptacle and providing a bath of molten slag for the succeeding pouring operation from said second mentioned pouring receptacle.

EDWARD B. STORY. EVARD P. BEST. 

